Dovecot - Secure IMAP and Pop3 server for Linux

Dovecot is an open source IMAP and POP3 email server for Linux or UNIX-like systems written with security primarily in mind. Dovecot is an excellent choice for both small and large installations. It is fast, simple to set up, requires no special administration and it uses very little memory. Dovecot is NOT responsible for receiving mail from other servers. Dovecot presents mail already stored on the system to mail-user agents [MUA].